When I was racing in the Carolinas it was very common to see a driver leaving in the backseat of a police car after purposefully wrecking a car on the track or fighting in the pits. I don't know what the full penalty was, but they were spending the night in jail. Mind you the cops were already at the track, so it wasn't a huge deal for them to take someone away.
Personally, I think banning from the track is a good policy. In an ideal world it would be nice if other tracks and series would enforce the bans. Unfortunately, too many tracks ban drivers for personal or mysterious reasons and it would be hard to be consistent on the policy.